Art of continuous distillation of hydrocarbon oils



July 10, 1928. 1,676,6U1

R. D. HUNNEMAN ART oF CONTINUOUS DISTILLATION op HYpRocARBoN oILs Filed March 27, 1925 Patented July l, lQZS.

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ROGER D. HUNNEMAN, 'OF CHECAGO, ILLINOS, ;..SSI(E-1{VOR T0 STANDARD OIL COMEANY, OF XVHTNG, INDIANA, A CORPORATN OF INDIANA.

ART OF CONTENUOUS DISTLLATIOH OF 'IYDROCARBON CELS.

Application filed 'l-arcli 27, 1925. Serial No. 18,818.

The present invention relates to improvements in the distillation ot hydrocarbon oils, and more particularly ot lubricating oils or distillates, tor the production of maximum quantities ot viscous lubricant residues and distillate products. lt will be fully understood trom the `following description, illustrated by the accompanying' drawing, in which ,is shown diagraminaticah ly a layout ot apparatus suitable tor carrying the invention into effect.

Reterring more particularly to the drawing, the numeral indicates a pipe still, in which the oil to be distilled is ted through the line 6. It desired, steam may be .supplied through the pipe 7 controlled by a Valve 8, or into the pipe still at any e'fuitable intermediate point. l? rom the pipe .ll 5 the oil, heated to the desired temperature, passes through the enlarged rquililnium conduit 9 to a chamber 10, ot substantial cross sectional areav .so that the velocity ot the vapors passing therethrough is n'iaterially lowered, and separation oitI vapors and uuvaporized liquid may take place.

From the separating chainber 10, unvaporized liquids pass out through the pipe or line 11. This line 11 is preferably provided with a. trap 12. and discharges into :io the upper portion ot a column 1S, which is supplied with tract-ionating` plates ot any suitable type; tor example, bubble plates 14- and disk and doughnut plates l5. ISteam supplied to the bottom ot the stripping column 13 through the line 16, and passes through the column in countercurrent to the descending liquid. tui-ther vaporizing and removing the lighter ends thereof. The proportion ot the steam may readily he controlled by means ot valve 17 to secure the desired characteristics (tor example, tlash point or gravity) ot' the residual product. Unvaporized residue is drawn ott through the valved line 18.

The steam and vapors removed thereby pass out of the top ot the column 13 through the line 19, and may suitably be introduced into the oil passing` through the pipe still 5 at an intermediate point ot the coil, as shown in the drawing.

From the separating chamber 10, vapors pass through the line 2O to a tractionatiug column 21, provided with tractionating plates ot any desired type; preterably low pressure drop plates at least above the point of admission ot vapors. In the fractionat ing tower 21 fractional condensation takes place, the condensate tormed descenoing to the base of the column and being` withdrawn through the valved discharge pipe Q2. llt desired, the condensing action ot the colun'ui may be controlled by the application ot a suitable cooling medium in the upper portion ot' the tower; tor example, water, raw oil, or other suitable cooling medium may be passed through the cooling coils 23 siiitably located therein. The i'incondensed oil and steam pass out ot the dephlegmating tower 21 through the Vapor line 24;. Provision is made tor the supply ot steam to the lower portion of the column 21 through the line 25 controlled by valve 26, so that steam may be employed, it desired, to ensure the removal ot lighter fractions trom the intermediate products drawn ott through the line 22.

The vapor line 2t leads to any suitable condensing device, and, il operation under vacuum is desired, any suitable means may be employed tor securing the desired vacuum. In the production ot lubricating oils.I

it is desirable that a high vacuum be maintained; tor example, an. absolute pressure ot millimeters or less may be maintained upon the system.

The process is particularly adapted tor the production ot viscous residues and distillates, particularly lubricating oils, trom crude and reduced crude oils ortrom distillates. Thus the feed stoel: may suitably be a heavy asphaltic oil having a gravity ot 21 A.. l). l., a viscosity of 900 seconds Saybolt at 1000 F. and a flash point of about to O F. It is brought in the pipe still 5to a temperature and pressure conditions prevailing being varied in accordance with the nature ot the product desired. From Yl to 6 pounds ot steam per gallon oit oil 'distillate may be supplied in the coil still. 5 and the towel` 13, trom one-tenth to one-halt of this being supplied in the tower 13 and the remainder through the steam line 7 directly into the pipe` still, with a temperature in the flash drum ot ($60O F., and employingl about fl pounds ot steam per gallon ot total oil distillate, ot' which about one-fourth is supplied inthe tower 18. a heavy ldistillate may he readily obtained in the tower 21 under subati'nospheric pressure conditions (about 53 mm. ot Hg) having a viscosity ot about 7 5() seconds Saybolt at 100O l?. and, a

fiash point ot about e900 F. The light distillate obtained from the vapors leaving tower 2l has a gravity of 25 to 26 A. P. l., a viscosity of t3 at 1000 F. an initialboiling point of 400 to 4200 F. and an end point ot 620 to 660 F. The residue obtained in tower 13 has a gravity of 1.004 at 770 F., a melting point ot 1220 F., a flash o'l` F., and contains 95% of constituents soluble in CS2, CCL, and hexane.

The vapors and steam separated from the unvaporiaed oil leave the chamber l0 and enter the tower 2l an ii "erniediate point. A partial eoi'idensation takes place therein, the heavier' portion of the oil being condensed and forming an intermeditae viscous fraction which is removed through the draw-ofi' line E22. The characteristics ot the intermediate distillate thus 'formed may be readily controlled by the injection ot a small. amount of steam through the line the supply of steam being controlled in accordance with the desired inspection tests oit the heavy distillate. These are, in general, flash point and viscosity. The lighter, uncon- 'densed portions of the. oil, together with the steam pass out through the vapor line Qfl to suitable condensing apparatus (not shown). VVl'ien conditions require a more careitul control et' the character ot the light condensate produced from the vapors issuing through the line 24, a cooling` coil Q3 may be employed in the top of the tower, water or oil being circulated thereto to control thel temperature et the issuing vapors.

lt is to be understoml that where proportions oit steam relative to oil distillate are hereinbefore referred to` the oil distillate is the sum total ot the condensates formed in the tower 21 and from the condensation ot the vapors passing out o't the tower through the line 24.

l claim:

l. The method of distilling hydrocarbon oils which comprises passing the oil in a confined stream through a heating Zone. discharging the oil into a separating` chamber, supplying steam in said chamber substantially the same temperature as the oil and in. thermal equilibrium therewith, separately removing unvaijiorized oil and vapors 'trom said chamber, subjecting the removed unvaporized oil to the action of live steam, thereby removing lighter fractions therefrom, withdrawing Ytrom the system the thus treated unvaporized oil, commingling the removed lighter fractions with the vapor contents of the separating chamber', subjecting the vapors removed from the separating chamber to a refluxing action and separately collecting the reflux termed.

2. The method ot distilling hydrocarbon oils which comprises passing the oil in a confined stream through a heating zone, dis-A cliarging the oil into a separating` chamber, supplying steam in said chamber at substantially the same temperature as the oil and in thermal equilibrium therewith, separately removing unvaporized oil and vapors J:'roiin said chamber, subjecting' the removed unvaporized oil to the action oit live steam, thereby removing lighter fractions therefrom, withdrawing from the system the thus treated unvaporiaed oil, commingling the removed lighter fractions with the vapor contents ot the separating chamber, subjecting the vapors removed from the separating chamber to a rel'luiing action, separately collecting the reflux formed and passing steam through lthe collected reliuX.

3. ln distillation apparatuifi, a heated coneuit. a separator into which said conduit lischarges, said separator effecting separation of vapors and unvaporized oils, a scrubbing tower, means i'or introducing unvaporized oil 'trom the separator into the scrubhing tower, means for introducing steam into die lower portion of said `scrubbing tower, means 'for securing the return of vapors from said scrubbing tower to the separator, a vapor conduit leading from the separator, and a tractionating tower into which said vapor conduit opens at an intermediate point, and means for separately withdrawing refluxr from said tower.

4. In distillation apparatus, a heated conduit, a separator into which said conduit discharges, said separator effecting separation ot vapors and unvaporized oils, a scrubhing tower, means `tor supplying unvaporized oil trom said separator to the scrubbing tower, means `for introducing steam into the lower portion of said scrubbing tower, means tor leading vapors from said scrubbing tower into the heating conduit, a vapor conduit leading from the separator, a fractionating tower into which the vapor conduit opens at an intermediate point, means tor introd ucing steam into the reflux tower below the opening of' the vapor conduit thereinto, and means tor separately withdrawing refiux fromv said tower.

5. In distillation apparatus, a heated conduit, a separator into which said conduit discharges, said separator effecting separation of vapors and unvaporized oils, a scrubbing tower, means for supplying unvaporizeil oil from said separator to the scrubbingl tower, means for introducing steam into the lower portion of said scrubbing tower, means for leading vapors from said scrubbing tower int-o the heat-ing conduit. a vapor conduit leading from the separator, a tractionating tower into which the vapor conduit opens at an intermediate point, and mean-s tor separately withdrawing reliux from said towerg ROGER D. HUNNEM A-hf'.-

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